Waitomo Caves, New Zealand

WAITOMO is a diminutive village with an outsize reputation for wonderful cave trips and magnificent karst features – streams that disappear down funnel-shaped sinkholes, craggy limestone outcrops, fluted rocks, potholes and natural bridges caused by cave ceiling collapses. Below ground, seeping water has sculpted the rock into eerie and extraordinary shapes. The ongoing process of cave creation involves the interaction of rainwater and carbon dioxide from the air, that together form a weak acid. As more carbon dioxide is absorbed from the soil the acid grows stronger, dissolving the limestone and enlarging cracks and joints, eventually forming the varied caves you see today.

The caves can be visited on a number of tours, from a gentle underground float through grottoes illuminated by glow-worms, to full-on wetsuit-clad adventure trips involving squeezes and hundred-metre abseils into the void. Alternatively you can go glow-worm-searching independently on a night-time walk through a natural tunnel.